ananyo writes: In a feature that recalls Asimov's Foundation series and 'psychohistory', Nature profiles mathematician Peter Turchin, who says he can see meaningful cycles in history. Worryingly, Turchin predicts a wave of violence in the United States in 2020.Quoting from the piece:To Peter Turchin, who studies population dynamics at the University of Connecticut in Storrs, the appearance of three peaks of political instability at roughly 50-year intervals is not a coincidence. For the past 15 years, Turchin has been taking the mathematical techniques that once allowed him to track predator–prey cycles in forest ecosystems, and applying them to human history. He has analysed historical records on economic activity, demographic trends and outbursts of violence in the United States, and has come to the conclusion that a new wave of internal strife is already on its way1. The peak should occur in about 2020, he says, and will probably be at least as high as the one in around 1970. “I hope it won't be as bad as 1870,” he adds.

Preceding the work of Peter Turchin is Richardson who published Statistics of Deadly Quarrels in 1950. Also Benoit Mandelbrot studied patterns in currency trading. before he began his fractal writing.

The problem here is multiple usages and meanings of "predict...", The problem is extrapolating numerical values into the future, as if one does a Fourier analysis of the past numerical values does not result in a table that accurately describes what will happen on a specific date in the future.